Alga Fucus Serratus Research Articles

Characterization of an algal extract by HPLC-ICP-MS and LC-electrospray MS for use in arsenosugar speciation studies

A large scale extract of the brown alga Fucus serratus was found to contain four arsenosugars (1–4) together with traces of dimethylarsinate (DMA) and arsenate by HPLC-ICP-MS. The extract was divided into 1500 equal subsamples which were then freeze-dried and stored at –18 °C. The homogeneity of this population of subsamples was established by random sampling and quantification of total arsenic by ICP-MS (1.22 µg As ±3.2%, mean ± RSD, n = 32) and hydride generation AAS (1.27 µg As ±2.0%, n = 32), and by quantification with HPLC-ICP-MS of the individual arsenic species in 10 subsamples: arsenosugar 1, 0.10 µg As ±3.6%; arsenosugar 2, 0.086 µg As ±2.9%; arsenosugar 3, 0.62 µg As ±3.8%; arsenosugar 4, 0.40 µg As ±3.1%; dimethylarsinate, 0.005 µg As ±20%; and arsenate ca. 0.001 µg As. The identity of the arsenosugars was confirmed by LC–electrospray (ES) MS with variable fragmenter voltage which provided simultaneous elemental and molecular detection. LC-ESMS was also used to quantify the four arsenosugars, producing values within 5% (2, 3 and 4) or 14% (1) of the ICP-MS data. The subsamples of Fucus extract provide a homogeneous source of natural material containing arsenosugars for use in arsenic speciation studies.

Concentrations of cadmium, copper, lead, nickel and zinc in the alga Fucus Serratus in the severn estuary from 1971 to 1995

Changes in the Cd, Cu, Ni, Pb and Zn concentrations in the mature thallus of the seaweed Fucus serratus collected from a lower-shore site in the heavily polluted Severn Estuary, (U.K), were recorded from 1971 to 1995. Over the period of observation Cd showed a dramatic reduction in concentrations whilst Pb showed low concentrations throughout the monitoring period due, it is suggested, to low of solubility/bioavailability of Pb in this environment with its high pH and high suspended-sediment load. Seasonal changes of Cd, Cu and Zn concentrations were observed in this alga. Concentrations of metals in the mature thallus, expressed as two-monthly means, showed highest values in March/April and lowest values in September/October.

The role of larval settling behaviour in determination of the specific habitat of the hydrozoan Dynamena pumila (L.) larval settlement in Dynamena pumila (L.)

Dynamena pumila (L.) lives on the brown alga Laminaria saccharina and Fucus serratus, in areas exposed to waves and currents. An experimental study of settling behaviour and metamorphosis of the planulae was conducted. Reconstruction of larval settlement showed that the colonies of D. pumila developed and fed in high flow environments, due not only to various adaptations of their morphology, but in great extent, due to the specific behaviour of larvae at, and prior to settlement and metamorphosis. Positive phototaxis by newly liberated planulae of D. pumila leads to colonization of illuminated zones on fucoid thalli and laminarian stipes and blades, where they metamorphosed in response to microbial films covering the algal surface. Crawling planulae of D. pumila were far more resistant to rapid water flows than the planulae of other hydroids, what allows this hydroid to establish its colonies in places with strong water movements, where the other species could not develop. Temporary exposure to air facilitated attachment and metamorphosis of the planulae, which probably settle and undergo metamorphosis during the periods of low-tidal emersion.

Fractal dimension as a quantitative measure of complexity in plant development

The shapes of 51 fronds from three species of brown algae (Fucus vesiculosus, Fucus serratus and Ascophyllum nodosum) were evaluated by computing the fractal dimensions (D) of their outlines. There was no difference in fractal dimension among mature fronds of the three species, and D was highly correlated with both developmental stage and structural complexity. With increasing age the plants grew not only larger but also more complex in form. Fractal dimension increased systematically with increasing complexity of shape from about 1 to 1.6. Fractal dimension thus provides a useful quantitative measure for the elaboration of shape complexity during plant development.

Algal carotenoids 54. Carotenoids of brown algae (Phaeophyceae)

The qualitative and quantitative carotenoid composition is reported for the brown algae Fucus serratus, F. vesiculosus, Ascophyllum nodosum, Pelvetia canaliculata, Laminaria digitala and L. saccharina. Emphasis was made on the identification of all minor carotenoids, on the demonstration of naturally occurring geometrical isomers and on the recognition of isolated artifacts. All- trans fucoxanthin was the major carotenoid (primary xanthophyll) and β,β-carotene the only carotene present in all six species. The diapoxidic all- trans violaxanthin was the second major xanthophyll. No acethylenic carotenoids were encountered amongst the minor carotenoids. These included cryptoxanthin-like, cryptoxanthin-5,6-epoxide-like, antheraxanthin-lie, latoxanthin-like and mactraxanthin-like carotenoids on the 0.01–1.5% of total carotenoid level, and the previously encountered zeaxanthin, neoxanthin (all- trans) and fucoxanthinol on the 0.01–0.02% of total carotenoid level. Violaxanthin and neoxanthin were partly isolated as the furanoid rearrangement products. Cis-isomers in general were isolation artificats. The chemosystematic implications are discussed. A biosynthetic scheme based on the carotenoids encountered is considered.

The Role of Ca2+ in Signal Transduction Following Fertilization in Fucus Serratus

ABSTRACT The marine brown alga Fucus serratus represents one of the few multicellular plant species in which the process of fertilization can be studied relatively easily. Fertilization marks the onset of a cascade of events associated with egg activation. Fertilization in Fucus serratus bears several superficial similarities to fertilization in several animal systems. The essential features of Fucus serratus egg activation are compared with those of protostome and deuterostome animal systems. Ca2+ is required for egg activation in Fucus serratus and cytosolic [Ca2+] changes can be observed in fertilizing eggs. However, these are small and variable in comparison with those occurring in deuterostomes, and fertilization can proceed normally in the absence of any global cytosolic Ca2+ transients. A model for egg activation in Fucus serratus is presented, invoking a role for both Ca2+ influx and localized propagation of the sperm signal around the plasma membrane by an as yet unidentified mechanism. Polarity in Fucus serratus is acquired a considerable time after fertilization and the role of cytosolic Ca2+ gradients in the acquisition and expression of polarity is discussed. The problem of the signals associated with the onset of the cell cycle in the fertilized Fucus serratus egg is also addressed.

Binding of monoclonal antibodies to vegetative tissue and fucose‐containing polysaccharides of Fucus serratus L.

SUMMARYMonoclonal antibodies (MAbs FS1–FS12) have previously been used to study the organization of cell surface glycoproteins on sperm and eggs of the brown alga Fucus serratus L. These antibodies were raised against Fucus sperm, but three (FS2, FS4 and FS5) also bind to the egg cell surface, and one (FS9) binds internally to polyphenol bodies in the egg. Evidence from immunofluorescence studies with the MAbs, using confocal laser scanning microscopy, has shown that the glycoproteins on the surfaces of both sperm and eggs are organized into domains. In the present study, the full set of MAbs was tested for cross‐reaction with F. serratus vegetative tissue in order to make a comparison with the gamete cell surfaces and to see whether any of the MAbs localized to particular regions of the mature thallus. A new MAb, FS13, which was raised to Fucus egg antigens, has also been characterized and used in this study. The results of ELISA, dot blot assays and indirect immunofluorescence tests show that the four MAbs which cross react with eggs (FS2, FS4, FS5 and FS9) also bind to vegetative tissue. Three MAbs (FS1, FS7 and FS12) bind to sperm and vegetative tissue, and MAbs FS3, FS6, FS8, FS10 and FS11 bind specifically to sperm. FS13 binds to egg vesicles and to vegetative tissue, but not to sperm. Western blotting and inhibition assays using ELISA have shown that the antigens recognized by the MAbs in vegetative tissue are different from those recognized on gametes, and glycoproteins on the latter are specific to each cell type (i.e. sperm or egg). Only FS7 and FS12 of the cross‐reacting MAbs recognize glycoproteins in vegetative tissue. They bind to most cell types, as does FS9 which recognizes polyphenols. The MAbs FS2, FS4, FS5 and FS13 all recognize fucose‐containing polysaccharides in vegetative tissue; however they recognize different epitopes and localize to different regions of the thallus. It is possible to distinguish between the amorphous matrix in the medulla which is FS13+, the mucilage at the plant surface which is FS2/5+ and the mucilage plug in the ostiole which is FS4+ FS2/5+. In addition FS13 and FS2/5 also label the walls of cells in the medulla. The results are compared with previous findings on the localization of fucoidan and ascophyllan in Fucus tissue.

INHIBITION OF FERTILIZATION IN FUCUS (PHAEOPHYCEAE) BY A MONOCLONAL ANTIBODY THAT BINDS TO DOMAINS ON THE EGG CELL SURFACE1

ABSTRACTFertilization in the brown alga Fucus serratus L. involves interactions between sperm and eggs and in species‐specific. Recent results with monoclonal antibodies(MAbs FS4 and FS5) that recognize glycoproteins on the Fucus egg cell surface have shown that different sets of glycoproteins are organized into distinct domains. Thus, regions on the egg surface are FS4+FS5− and FS4−FS5+, and some smaller regions are FS4+FS+. To determine functional differences between these domains, MAbs FS4 and FS5 were included in a fertilization assay, Purified FS5 antibody, which is an immunoglobulin class M (IgM), inhibited fertilization, whereas FS4 IgM had no effect, Fragment antigen‐binding fragment, which suggests that the effects were not due to steric hindrance by large IgM molecules or to cross‐linking of receptors. FS5 inhibited fertilization in both F. serratus and F. vesiculosus; therefore, its effect was not species‐specific, Thus we show that there is functional heterogeneity of the Fucus egg cell surface and compare our results to previous reports on inhibitory effects of lectins, Overall, the evidence suggests that there may be two levels of interaction between gametes in Fucus involoving nonspecific and species‐specific binding.

The effect of predation on the life histories of Littorina obtusata and Littorina mariae

Littorina obtusata is an epiphytic gastropod which lives for three to four years on its host Ascophyllum nodosum, a long-lived brown alga. Most of the population consists of adults, present throughout the year in the size range 14 to 17 mm. Newly hatched individuals appear between April and October with a peak in July; the immature winkles grow to merge with the adult cohort in May.In contrast Littorina mariae is an annual; newly hatched individuals grow to maturity by the winter of their first year. Those reaching maturity overwinter as adults but very few live beyond spring of their second year. The population dynamics of L. mariae are closely linked with changes in the biomass of the alga Fucus serratus on which it lives.

The molecular nature of Fucus serratus sperm surface antigens recognised by monoclonal antibodies FS1 to FS12

Sperm of the brown alga Fucus serratus are highly differentiated, biflagellate, naked cells. Immunolocalisation studies, employing monoclonal antibodies (MAbs - designated FS1 to FS12) raised against antigens of these sperm cells, have revealed that some sperm surface components are distributed over the entire cell, whereas others are restricted to, or occur preferentially on, the surface of the anterior flagellum or cell body. This report describes the use of these MAbs in Western-blot procedures and antigen-modification binding assays to determine the nature of these sperm surface components. Monoclonal antibodies which bind to antigens found on the cell body and both flagella (FS3, FS4, FS6, FS8, FS10) recognise carbohydrate epitopes of a high-molecular-weight glycoprotein (Mr=205 kDa). These MAbs were initially chosen at random from a much larger number of antibodies which bound to sperm in a similar fashion, indicating that this glycoprotein is an immunodominant antigen. Though these MAbs compete under conditions of limited antigen availability, differences in the effects of periodate on antibody binding and differences in other binding data indicate that the MAbs recognise epitopes of this glycoprotein which are neighbouring or overlapping, rather than common. The MAb FS9, which has a similar binding pattern to the above antibodies, also seems to bind to carbohydrate epitopes, but the antigen recognised by this antibody could not be identified in Western-blotting procedures. The MAbs FS7 and FS12, which bind to the mastigonemes on the anterior flagellum and to the cell body and posterior flagellum, recognise a set of glycoproteins in the molecular-weight range 40-250 kDa. The evidence indicates that the antibodies are binding to N-linked carbohydrate side chains of these glycoproteins. Three MAbs that bind to the anterior flagellum (FS2, FS5 and FS11) recognise protein antigens in the molecular-weight range 90-250 kDa; it is not known whether these antigens are glycosylated. The MAb FS1, which binds primarily to the sperm cell body, could not be used in enzyme-linked immunosorbent assays or Western-blotting procedures and the antigen recognised by this antibody is so far uncharacterised.

Littorina mariae ? a factor structuring low shore communities?

The role of littorinids in structuring communities is discussed. On hard substrates preferential grazing of the dominant algae often enables competitively inferior species to utilize the rock substrate. Investigations of these systems has led to the proposal of a number of factors that should be analyzed in order to assess the effect of herbivores on community structure. Some of these factors have been investigated for Littorina mariae Sacchi & Rastelli. L. mariae is a micro-epiphytic grazer browsing the surface covering of epiphytes off the alga Fucus serratus (L.). The relationship between the host alga, F. serratus, and L. mariae is far more intricate than that between winkles and hard substrates as the alga itself is a dynamic resource. L. mariae is spatially and temporally linked to F. serratus. L. mariae is found almost exclusively on the alga and is positively attracted by extracts of the alga. The life history of the winkle is closely synchronized with that of the alga (the winter decrease of L. mariae populations is associated with the seasonal die-back of the host alga). On analysis of the factors considered important to assess herbivory, and examples of the effects of other epiphytic herbivores on algal success, it is suggested that L. mariae could potentially play an important role in structuring the community of it's host fucoid and that this may influence larger scale community structure. Experimental manipulations are proposed to evaluate these hypotheses.

Factors influencing the uptake of technetium by the brown alga Fucus serratus

Various experiments on the brown alga Fucus serratus, under light, in darkness, at two different temperatures (4 and 20°C) and after heat-inactivation, suggest that the accumulation of technetium is a physiologically controlled process. This hypothesis is supported also by chromatographic analyses of algal extracts, in which the proportion of technetium bound to organic molecules was found to be higher under light than in darkness or at 4°C.

Monoclonal antibodies to sperm surface antigens of the brown alga Fucus serratus exhibit region-, gamete-, species- and genus-preferential binding

A panel of twelve monoclonal antibodies (MAbs), designated FS1 to FS12, have been raised against surface antigens of Fucus serratus sperm. The antibodies were selected on the basis that they show region-, gamete-, species- or genus-preferential binding. Indirect immunofluorescence shows that the antigens bound by the MAbs are distributed non-randomly over the cell surface. Seven MAbs (FS1, FS3, FS4, FS6, FS8, FS9, FS10) bind antigens located primarily on the cell body, while the others (FS2, FS5, FS7, FS11, FS12) bind antigens located primarily on the anterior flagellum. Of the MAbs that label the anterior flagellum, FS2, FS5, FS7 and FS12 form a 'halo' at the perimeter of the flagellum. Electron microscopic-immunogold studies indicate that the 'halo' results from labelling of the mastigonemes, as opposed to the flagellar plasmamembrane. Gamete-preferential binding of antibodies was detected using an enzyme-linked immunosorbent assay with egg membrane vesicles. Eight of the MAbs bind sperm antigens not common to eggs, though FS2, FS4, FS5 and FS9 bind antigens present on both sperm and eggs. In studies of species- and genus-specificity FS2, FS3, FS5, FS6, FS7, FS8, FS10, FS11 and FS12 exhibit genus-preferential binding, labelling sperm of F. serratus and F. vesiculosus more intensely than that of Ascophyllum nodosum. Only FS10 showed marked species-preferential binding, labelling sperm of F. serratus much more intensely than that of F. vesiculosus.

The influence of neighbors on the feeding of an epifaunal bryozoan

In North Wales the encrusting bryozoans Electra pilosa (Linnaeus), Alcyonidium hirsutum (Fleming), and Flustrellidra hispida (Fabricius) are epifaunal on the fucoid alga Fucus serratus (Linnaeus). Colonies occur in close proximity and overgrowth frequently results. This study experimentally demonstrates how suspension-feeding of Electra is affected by degree of association with neighboring colonies and by ambient flow velocity. In slow flow, feeding of Electra colonies was reduced when Alcyonidium colonies were present upstream. An even greater reduction in feeding occurred when Alcyonidium colonies surrounded Electra. However, evidence suggests that such reduction in feeding should be only a transient phenomenon in natural habitats because of the very short duration of low-flow velocities during the tidal cycle. In faster flow, Electra feeding was greater when Alcyonidium colonies were present upstream, and greater still when Alcyonidium colonies surrounded Electra. Similarly, feeding of Electra surrounded by Flustrellidra colonies in fast flow was greater than that of isolated Electra colonies or of colonies downstream from Flustrellidra: there was no apparent difference in Electra feeding in the latter two cases. Isolated Electra colonies experienced a general reduction in feeding success with increased flow velocity, however, colonies showed a greater propensity to feed as flow velocity increased. The enhanced feeding of Electra in association with other colonies in fast flow likely results from the slowing and diverting of flow by Alcyonidium and Flustrellidra. This study provides evidence that feeding enhancement in encrusting assemblages is an important phenomenon.

Feeding-current interactions and competition for food among the bryozoan epiphytes of Fucus serratus

Flustrellidra hispida (Fabricius), Alcyonidium hirsutum Fleming and Electra pilosa (L.), generally the three most abundant bryozoan epiphytes of the intertidal brown alga Fucus serratus L, were collected around low-tide mark at Port St. Mary, Isle of Man (UK), during 1983 and early 1984. Flustrellidra hispida is far larger than the other two species. Direct measurements of feeding-current velocities within the lophophores of competing colonies indicate that F. hispida is able to adversely affect the feeding of adjacent colonies of competing bryozoan species. Results suggest that among the bryozoan community of Fucus serratus, competition for food and for space are closely linked and that both are significant components of interspecific competition.

Changes in the lipid metabolism of fucus serratus and fucus vesiculosus caused by copper

The effect of copper on lipid metabolism in the brown algae Fucus serratus and Fucus vesiculosus was studied. Experiments in vitro showed that elevated Cu 2+ increased the relative labelling of lipids from [ 14C]acetate without altering total uptake. An alteration in the pattern of fatty acids synthesised was also seen with an increase in the relative labelling of oleate and a decrease in that of palmitate. These differences in metabolism were also seen when algae from sites polluted by copper were compared to samples collected from non-polluted areas. The above changes are discussed with regard to the relative tolerance of Fucus spp. to high environmental dissolved copper levels.

Lipids and lipid metabolism in the brown alga, Fucus serratus

The lipids of the brown alga Fucus serratus were isolated, identified and quantified. The major acyl lipids were the three glycosylglycerides, diacylgalactosylglycerol, diacyldigalactosylglycerol and diacylsulphoquinovosylglycerol. These represent over 70% of the total acyl lipids. The fatty acid compositions of the major lipids were examined and most showed rather distinctive fatty acid contents. For example, diacylgalactosylglycerol was enriched in n-3 polyunsaturated fatty acids while phosphatidylcholine and phosphatidylethanolamine had very high levels of arachidonate. Phosphatidylglycerol contained the unusual trans-Δ3-hexadecenoic acid. The labelling of lipids and fatty acids from [ 14C]acetate was examined and the distribution of label between individual components as a function of the incubation period and in algae collected at different times of the year is reported. Algae collected in the winter incorporated much more radioactivity into non-esterified fatty acids when compared to algae collected in the summer. All algae could label myristate, palmitate, stearate and oleate at high rates. Longer incubation times allowed the labelling of polyunsaturated fatty acids such as linoleic acid.

The effect of trace metals on lipid metabolism in the brown alga Fucus serratus

The effect of trace metals on lipid metabolism in the brown alga <i>Fucus serratus</i>

Specificity of sexual chemotaxis in fucus serratus and fucus vesiculosus (phaeophyceae)

Summary The conjugated octatriene fucoserraten is the substance secreted by eggs of the brown alga Fucus serratus to excite and attract spermatozoa. Threshold concentrations for synthetic fucoserraten, nine other octatriene isomers and n-hexane were determined using spermatozoa of Fucus serratus and F. vesiculosus . The strongest attraction occurred between spermatozoa of both species and fucoserraten. There is no species- specificity on the level of gamete-chemotaxis, which is confirmed by the occurrence of intense interspecific attraction, n-hexane is 3100 times less active than fucoserraten, which indicates that this substance is not the native attractant in Fucus vesiculosus as suggested by other authors. Experimental evidence is presented that the male chemotactic response is poorly developed in an isogamous system (Ectocarpus), whereas male gametes in anisogamous and oogamous systems (Cutleria and Fucus) are significantly more reactive.

Sulphate Uptake inFucus serratus

The brown alga Fucus serratus Linn has been shown to possess an active sulphate uptake system, which is blocked by the metabolic inhibitors DNP and DCCD, but not by the photosystem II inhibitor DCMU. The affinity of the system for sulphate was 5.9 × 10−5 M, and a monophasic response to external sulphate concentration was found in the range 10−6–10−3 M. Sulphate uptake was also inhibited by the Group VI anions selenate and chromate. Short-term kinetic experiments showed an initial hyperbolic uptake of S35O42- for 20 s probably representing diffusion into the intracellular free spaces of the alga, after which sulphate uptake was linear. The intermediates of the sulphate activating system, APS and PAPS, appeared in the alga after 20 s and cysteine after 1 min. The sulphate intermediary metabolic pools were saturated after 2 min, and radioactivity was linearly incorporated into the sulphated fucan, fucoidan, after 2 min. A chase period of 15 min confirmed that the sulphate activating system SO42- →APS→PAPS occurs in Fucus serratus. The principal metabolic fate of the assimilated sulphate was esterification to fucoidan (80% of the total 35S present after a 1 h pulse) and assimilatory sulphate reduction to the sulphur amino acids was a minor pathway in this alga. The turnover of sulphate in fucoidan was rapid (t0.5 20 h) and was much higher than the corresponding turnover of carbon under optimal photosynthetic conditions. This suggested that a preexisting polymer was sulphated; there was also no evidence for sulphated sugar nucleotides in the short-term kinetic experiments.